Constant pressure screw extractor with right-angularly adjustable supporting structure



Jan. 7, 1958 R. G. MILLER 2,818,894

CONSTANT PRESSURE SCREW EXTRACTOR WITH RIGHT-ANGULARLY ADJUSTABLE SUPPORTING STRUCTURE Filed Sept. 24, 1956 INVENTOR.

A 17 V 5 M/ZM/Q ATTD RN EYE United W 8 Patent CONSTANT PRESSURE SCREW EXTRACTOR WITH RIGHT-ANGULARLY ADJUSTABLE SUPPORT- ING STRUCTURE Roy G. Miller, Honolulu, Territory of Hawaii Application September 24, 1956, Serial No. 611,578

2 Claims. (Cl. 144-32) This invention relates to a tool, and more particularly to a tool for use in extracting or removing screws.

The object of the invention is to provide a constant pressure screw extractor which will permit screws to be extracted or withdrawn with greater facility and with a stant pressure screw extractor which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same.

Figure 1 is a perspective view illustrating the constant pressure screw extractor of the present invention being used.

Figure 2 is a sectional view taken on the line 2--2 of Figure 1.

Figure 3 is a sectional view taken on the line 33 of Figure 2.

, Figure 4 is a sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a sectional view taken at rightv angles to the view shown in Figure 4, and showing the ratchet.

Figure 6 is a sectional view taken on the line 66 of Figure 3.

Referring in detail to the drawings, the numeral 10 indicates a portion of a supporting structure or body which may have a cover plate 11 detachably connected thereto through the medium of suitable securing elements such as the screws 12, Figure 1. The present invention is directed to a constant pressure screw extractor whereby the screws such as the screws 12 can be more easily extracted or withdrawn, as for example when the plate 11 is to be removed from the body 10. The screw extractor of the present invention includes, in Figure 1,

aframe 13, but it is to be understood that the present.

invention is not restricted to any particular type of frame as later described in this application. The frame 13 includes a pair of spaced parallel side members 14 and spaced parallel end member 15. A crossbar 16 is adjustably connected to the frame 13, and the ends of the crossbar 16 slidably engage the side members 14 of the frame. Adjustably connected to the crossbar 16 is a screwblock 17, and the screw block 17 is mounted for sliding'movement along the crossbar 16. Thus, due to the provision of the adjustable crossbar 16 and the screw v the screws can be readily removed regardless 1 of their location since the tool can be shifted without the necessity of shifting the entire frame.

The screw block 17 is provided with a longitudinally extending bore that defines a lower recess 18, Figure 2. A sleeve 19 is detachably seated in the recess 18. The recess 18 defines within the screw block 17 a shoulder 22, and the'upper end of the sleeve 19 abuts the shoulder 22. An enlarged head 20 is formed on the lower end of the sleeve 19, Figure 6, and the head 20 is snugly seated in a slot or cutout 21 in the lower end of the screw block 17. For maintaining the sleeve 19 in the recess 18, a suitable securing element such as the screw 24 extends through the screw block 17 and into engagement with a socket or cutout 23 in the side of the sleeve 19. A suitable cap 25 may be connected to the upper end of the screw block 17 through the medium of screws or bolts When a frame such as the frame 13 is used, there may be provided a plurality of supporting legs 27, Figures 1 and 2. The legs 27 may have their upper ends connected to the side members 14 of the frame through the medium of bolts 28, while the lower ends of the legs 27 may be anchored to the plate 11 through the medium of anchor pins or bolts 29.

The sleeve 19 is provided with a longitudinally extending threaded opening 30, and a drive screw 31 is arranged in threaded engagement with the opening 30. The upper end of the drive screw 31 may be tapered as at 32, and a socket member 33 is mounted on the upper end portion 32. A handle 34 has its lower end connected to the socket member 33. A ratchet 35 is connected to the lower end of the drive screw 31, and a screw point or blade 36 is arranged below the ratchet 35. The ratchet 35 is shown in detail in Figures 4 and 5 and it is deemed that the ratchet 35 may include a hollow casing or housing 37 which has pawls or dogs 38 arranged therein, and the pawls 38 are adapted to engage teeth 39.

From the foregoing, it is apparent that there has been provided a constant pressure screw extractor which is especially suitable for use in removing screws such as the screws 12 from any suitable supporting structure. While the present invention has been illustrated as being used from a frame 13, it is to be understood that the principle of the present invention can be incorporated in other structures besides the frame 13.

As previously described, when the frame 13 is used,

side members 14 of the frame 13 so that the screw extractor is above the screw to be removed. As a further adjustment, the screw block 17 can be slid or moved along the crossbar 16 so as to properly position the extracting tool with respect to the screw being extracted. The screwdriver blade 36 is adapted to be detachably connected to a shank 40 which is arranged below the ratchet 35, so that by arranging the blade 36 in engagement with the kerf of the screw 12 and properly rotating the handle 34 the screw can be extracted or removed. After a screw has been removed, the tool can be shifted to the next location so that succeeding screws can be;

removed with the tool of the present invention.

As previously described, the present invention is not to be restricted to any particular frame 13 since it is' contemplated that the invention wil be used in a mobile stand or an overhead train. The pointed upper end 32 at the top of the drive screw 31 is adapted to be con-.

shoulder 22 provides the necessary strength to withstand; the upward force of the drive screw. Also, the hexagonal shaped head 20, Figure 6, fits into the keyway 21 at the bottom 'arthsnewbieekinso as to prevent rotation of the sleeve 19. The set screw 24 fits into or engages the recessed-portion 2 3, of. the,sleeve 19 soas to prevent the neevenarh ac dentallyifallingiout.of. thebo t tom of the block. ,Theso ct 331is'detachab'le. and thesleeve19 is.al so jdeta'cjliableor removable, and the ratchet may also be removable. It is to belunderstood that sleeve assemblies o'f. various sizes and various threads per inch. may beinterchangeablelin thesamescrew block. Furthermore, infjthe event that'thejdrive sercwis damaged as for exarhplelin the. event the threads become stripped, "itis not necessar to discard the entire screw'iblocksincelonly the .darria parts nee'dbel replaced."

The entire mechanjsmfincludir g the frame "13 and the screw blockassemblyconstitutes fa eonsjtantpressure screw extractorjbut itis tofbe understood thatthe screw block assembly is the 'irnportant part of th'e present inventionsincethe frame f'has Qnly'l'beenused in an'illustrative sens'e and "noti'n a limiting sense. The frame only functions to position the screwblock assembly and to "provide a rigid foundationfor the. screw block assembly'when it exerts pressure.

The'operation of 'the screw extractoris as follows. The frame '13 is tb'olted or otherwise secured to a surface andthe traveling cross bar'16' and screwblock assembly are adjusted over"the screw fto heremoved. The speed handle 34 is, inserted in the socket33. and the handle 34 is rotated. This turns orgrot ates the threaded drive screw 31 downward throug h the screw block 17 so that the screw driver point 36"cont-acts fthe screw j'12to be removed. The-handle '34 isdhenfurther rotated so that thedrive screw'31 continues in downward rotation but the blade 36 and screw "12 to be removed do not further'rot-ate, since the-ratchet 35-permitsthe drive screw 31 to continue downward rotation without'further rotation of the-blade -36-and screw 12. Thus, the downward pressure upon the screw 12 is increased to whatever amount is .desiredwhereby the screw point or blade 36 is held firmly in thescrew to be removed. The rotation of the socket-33 is then reversed'whereby the entire assembly rotates upward,-but the'downward pressure upon the screw 12 to be removed remains constant. Thus, the screw point .36 remains firmly secured within the screwto. be removed although both are rotating upward as the drive screw 31 is retracted. Since the threads onthe .drivescrew 31'are'of thesame number per inch as;those.on.the screw tobe removed, both'rotate upward at the same rate of speed. After the screw has been completely .-removed, .the entire screwblock assembly is moved or adjusted overthe next screw to be removed and thewholeoperation. is repeated.

.As a. specific exampleof the use of the tool'the following is given. Throughout industry, and particularly the airplane maintenance field, various inspection and access plates are provided which contain a plurality of screws that must be removed so that the interior machinery can be inspected and entered. For example, in certain types of airplanes, access plates contain about 200 flush headscrews .all of which must be removed and require many hours of work. .Also, the screws have a tendency to corrode so .that the removal of the screws is made morezdifiicult an'd.the.hand motion-of the person using the screwdriverorjscrewgun often causes damage to the areasurrounding. the screws andto the screwheads themselves. With the presentinvention such difiiculties are overcome and the time necessary for the removal of the .screws from .an inspection plate such as the plate 11,is reduced and there is noinjury to the screwheads or the surrounding area. The .:frame 13 may have its legs 27 bolted tothe plate 11 by means ofthe bolts 29 and the.frame has the traveling .crossbar 16 whereby any poinffbeneath the framecan be reached. The crossbar carriesthemoving screw block 17 and the screw block includes 'the threaded drive screw .which has the .speed handle 34 connected thereto, there being a ratchet on the bottom "of the drive screw. "A screwdriver pointis connected to the ratchet and the screwdriver point is of a size which corresponds to the screws being removed. The threads on the drive screw are of the same number per inch as the threads on the screw to be removed.

The extractor of the present invention is operated by adjustingthe crossbar and screw block .assemblyover thescrew .tobe removed and then "the drive screw-Skis screwed downward until the screwdriver-point 36 makes contact with the screw head. The drive screw 31 is then screwed further down but will not turn the screw 12 because the ratchet SSperrnits the downward rotation of thedr'ive" screw without rotation of the screw to be removed, and this-results in pressure being placed against the screwhead without turning it so that the screwdriver point is held exactly in the screwhead. Then, the entire device is unscrewed. and the drive .screw assembly-retracts the screw to be removed while the .pressure .on the screw head remains constant. Due to the exact correlation of the threads per inchin the drive screw, the screw to'be removed comes out evenly and smoothly and after the screw has been completely removed, the crossbar and screwblock are moved over the next. screw.

Any shape 'of frame canbeused and the basic principle of the present invention isto utilize a rigid frame whereby :the "operatofls movements will not shake the screwdriver point from the screw .head after the drivescrew andratchet have applied, pressure to the screw head.

-While the present invention has been illustrated being used with ,a manually operable drive screw, it is to .be understood that thepresent invention may be used with a' motor driven drive screw instead of a manual speed wrench. Furthermore, theratchet'maybe detachable.

1. In a constant pressure gscrew extractor, a frameineluding spaced parallel side memhers and spaced, parallel end members, a plurality of legs depending -'from.said frame and adapted to be secured to a supporting structure, acrossbar'adjustably connected to said frame 'and mounted for adjustment along a longitudinal axis thereof, a screw block adjustably connected to said crossbar andmounted for adjustment-along an axis which'is at right angles to the longitudinal axis .of the frame, said screw block being provided with a longitudinally extending bore defining a recess extending .upwardlyfrom the bottom-of said screw block, said-recess defining in ,said screw block a shoulder, a sleeve seated insaid recess and :having its upper end abutting said shoulder, a securing .element extending through said screw block and engaging said sleeve, there being a threaded opening in said sleeve, a drive screw arranged in threadedengagement with :thevthreaded opening in said sleeve, 'a'socket memberconnectedstothe upper end of said drive screw, a handle .detachably connected to said socket member, aratchet connected .to the-lower end of said drive screw, and a-screw epoint sarranged beneath said ratchet, there being a slot inthelower'end of said screw bloclgahead on the lowerend of said .sleeve seated in said slot, and a cap connected .to=the upper endof said-screw block.

2. I i1-a eonstantpressure screw-extractor, a frame includingspaced parallel sidetmembers and spaced parallel end members, a plurality .of .legs depending from said frame ,and adaptedv to be secured to 'a supporting structure, a crossbar adjustably connected tosaid frame, and mounted for adjustment along a longitudinal axis thereof, a screw "block adjustablyconnected to :said crossbar and mounted for adjustment along an .axis which is at right angles to the longitudinal axis of the .frame, said screw block being-provided with a longitudinally extend,- ing boredefi-n'ing a recess extending upwardly from the bottom'o'f said screwblock, said recess definingin -said screw 'bloek a shoulder, a sleeve seated and having its upper end abutting said shoulderga .securing element extending through said screw blot-k and engaging said sleeve, there being a threaded opening in said sleeve, a drive screw arranged in threaded engagement with the threaded opening in said sleeve, a socket member connected to the upper end of said drive screw, an operating means detachably connected to said socket member, a ratchet detachably connected to the lower end of said drive screw, and a screw point arranged beneath said ratchet.

References Cited in the file of this patent UNITED STATES PATENTS Ray Mar. 27, 1951 Wales Dec. 30, 1952 Henry Dec. 30, 1952 Becker Sept. 8, 1953 

